Hey @kohki - we open source a lot of stuff, but not everything.
Currently, the main things that are closed source are our APIs and our drag and drop editor (though they are highly customizable with your own React components via plugins).
Virtually everything else we do is open source. You can read in detail what we open source vs don’t here
Re: lists we show up on, we don’t list our full platform anywhere as being open source, if anywhere you read suggests otherwise you could reach out to them for a correction
Re: self hosting, currently this is not an option we offer, but something we are considering for the future